6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Janusz Krzysztofik janusz.krzysztofik@linux.intel.com
[ Upstream commit 78b4d6463e9e69e5103f98b367f8984ad12cdc6f ]
A timer that expires a vgem fence automatically in 10 seconds is now released with timer_delete_sync() from fence->ops.release() called on last dma_fence_put(). In some scenarios, it can run in IRQ context, which is not safe unless TIMER_IRQSAFE is used. One potentially risky scenario was demonstrated in Intel DRM CI trybot, BAT run on machine bat-adlp-6, while working on new IGT subtests syncobj_timeline@stress-* as user space replacements of some problematic test cases of a dma-fence-chain selftest [1].
[117.004338] ================================ [117.004340] WARNING: inconsistent lock state [117.004342] 6.17.0-rc7-CI_DRM_17270-g7644974e648c+ #1 Tainted: G S U [117.004346] -------------------------------- [117.004347] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. [117.004349] swapper/0/0 [HC1[1]:SC1[1]:HE0:SE0] takes: [117.004352] ffff888138f86aa8 ((&fence->timer)){?.-.}-{0:0}, at: __timer_delete_sync+0x4b/0x190 [117.004361] {HARDIRQ-ON-W} state was registered at: [117.004363] lock_acquire+0xc4/0x2e0 [117.004366] call_timer_fn+0x80/0x2a0 [117.004368] __run_timers+0x231/0x310 [117.004370] run_timer_softirq+0x76/0xe0 [117.004372] handle_softirqs+0xd4/0x4d0 [117.004375] __irq_exit_rcu+0x13f/0x160 [117.004377] irq_exit_rcu+0xe/0x20 [117.004379] sysvec_apic_timer_interrupt+0xa0/0xc0 [117.004382] asm_sysvec_apic_timer_interrupt+0x1b/0x20 [117.004385] cpuidle_enter_state+0x12b/0x8a0 [117.004388] cpuidle_enter+0x2e/0x50 [117.004393] call_cpuidle+0x22/0x60 [117.004395] do_idle+0x1fd/0x260 [117.004398] cpu_startup_entry+0x29/0x30 [117.004401] start_secondary+0x12d/0x160 [117.004404] common_startup_64+0x13e/0x141 [117.004407] irq event stamp: 2282669 [117.004409] hardirqs last enabled at (2282668): [<ffffffff8289db71>] _raw_spin_unlock_irqrestore+0x51/0x80 [117.004414] hardirqs last disabled at (2282669): [<ffffffff82882021>] sysvec_irq_work+0x11/0xc0 [117.004419] softirqs last enabled at (2254702): [<ffffffff8289fd00>] __do_softirq+0x10/0x18 [117.004423] softirqs last disabled at (2254725): [<ffffffff813d4ddf>] __irq_exit_rcu+0x13f/0x160 [117.004426] other info that might help us debug this: [117.004429] Possible unsafe locking scenario: [117.004432] CPU0 [117.004433] ---- [117.004434] lock((&fence->timer)); [117.004436] <Interrupt> [117.004438] lock((&fence->timer)); [117.004440] *** DEADLOCK *** [117.004443] 1 lock held by swapper/0/0: [117.004445] #0: ffffc90000003d50 ((&fence->timer)){?.-.}-{0:0}, at: call_timer_fn+0x7a/0x2a0 [117.004450] stack backtrace: [117.004453] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G S U 6.17.0-rc7-CI_DRM_17270-g7644974e648c+ #1 PREEMPT(voluntary) [117.004455] Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER [117.004455] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR4 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023 [117.004456] Call Trace: [117.004456] <IRQ> [117.004457] dump_stack_lvl+0x91/0xf0 [117.004460] dump_stack+0x10/0x20 [117.004461] print_usage_bug.part.0+0x260/0x360 [117.004463] mark_lock+0x76e/0x9c0 [117.004465] ? register_lock_class+0x48/0x4a0 [117.004467] __lock_acquire+0xbc3/0x2860 [117.004469] lock_acquire+0xc4/0x2e0 [117.004470] ? __timer_delete_sync+0x4b/0x190 [117.004472] ? __timer_delete_sync+0x4b/0x190 [117.004473] __timer_delete_sync+0x68/0x190 [117.004474] ? __timer_delete_sync+0x4b/0x190 [117.004475] timer_delete_sync+0x10/0x20 [117.004476] vgem_fence_release+0x19/0x30 [vgem] [117.004478] dma_fence_release+0xc1/0x3b0 [117.004480] ? dma_fence_release+0xa1/0x3b0 [117.004481] dma_fence_chain_release+0xe7/0x130 [117.004483] dma_fence_release+0xc1/0x3b0 [117.004484] ? _raw_spin_unlock_irqrestore+0x27/0x80 [117.004485] dma_fence_chain_irq_work+0x59/0x80 [117.004487] irq_work_single+0x75/0xa0 [117.004490] irq_work_run_list+0x33/0x60 [117.004491] irq_work_run+0x18/0x40 [117.004493] __sysvec_irq_work+0x35/0x170 [117.004494] sysvec_irq_work+0x47/0xc0 [117.004496] asm_sysvec_irq_work+0x1b/0x20 [117.004497] RIP: 0010:_raw_spin_unlock_irqrestore+0x57/0x80 [117.004499] Code: 00 75 1c 65 ff 0d d9 34 68 01 74 20 5b 41 5c 5d 31 c0 31 d2 31 c9 31 f6 31 ff c3 cc cc cc cc e8 7f 9d d3 fe fb 0f 1f 44 00 00 <eb> d7 0f 1f 44 00 00 5b 41 5c 5d 31 c0 31 d2 31 c9 31 f6 31 ff c3 [117.004499] RSP: 0018:ffffc90000003cf0 EFLAGS: 00000246 [117.004500] RAX: 0000000000000000 RBX: ffff888155e94c40 RCX: 0000000000000000 [117.004501] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [117.004502] RBP: ffffc90000003d00 R08: 0000000000000000 R09: 0000000000000000 [117.004502] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000246 [117.004502] R13: 0000000000000001 R14: 0000000000000246 R15: ffff888155e94c80 [117.004506] dma_fence_signal+0x49/0xb0 [117.004507] ? __pfx_vgem_fence_timeout+0x10/0x10 [vgem] [117.004508] vgem_fence_timeout+0x12/0x20 [vgem] [117.004509] call_timer_fn+0xa1/0x2a0 [117.004512] ? __pfx_vgem_fence_timeout+0x10/0x10 [vgem] [117.004513] __run_timers+0x231/0x310 [117.004514] ? tmigr_handle_remote+0x2ac/0x560 [117.004517] timer_expire_remote+0x46/0x70 [117.004518] tmigr_handle_remote+0x433/0x560 [117.004520] ? __run_timers+0x239/0x310 [117.004521] ? run_timer_softirq+0x21/0xe0 [117.004522] ? lock_release+0xce/0x2a0 [117.004524] run_timer_softirq+0xcf/0xe0 [117.004525] handle_softirqs+0xd4/0x4d0 [117.004526] __irq_exit_rcu+0x13f/0x160 [117.004527] irq_exit_rcu+0xe/0x20 [117.004528] sysvec_apic_timer_interrupt+0xa0/0xc0 [117.004529] </IRQ> [117.004529] <TASK> [117.004529] asm_sysvec_apic_timer_interrupt+0x1b/0x20 [117.004530] RIP: 0010:cpuidle_enter_state+0x12b/0x8a0 [117.004532] Code: 48 0f a3 05 97 ce 0e 01 0f 82 2e 03 00 00 31 ff e8 8a 41 bd fe 80 7d d0 00 0f 85 11 03 00 00 e8 8b 06 d5 fe fb 0f 1f 44 00 00 <45> 85 f6 0f 88 67 02 00 00 4d 63 ee 49 83 fd 0a 0f 83 34 06 00 00 [117.004532] RSP: 0018:ffffffff83403d88 EFLAGS: 00000246 [117.004533] RAX: 0000000000000000 RBX: ffff88888f046440 RCX: 0000000000000000 [117.004533] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [117.004534] RBP: ffffffff83403dd8 R08: 0000000000000000 R09: 0000000000000000 [117.004534] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff837cbe80 [117.004534] R13: 0000000000000004 R14: 0000000000000004 R15: 0000001ad1df466b [117.004537] ? cpuidle_enter_state+0x125/0x8a0 [117.004538] ? sched_clock_noinstr+0x9/0x10 [117.004540] cpuidle_enter+0x2e/0x50 [117.004542] call_cpuidle+0x22/0x60 [117.004542] do_idle+0x1fd/0x260 [117.004544] cpu_startup_entry+0x29/0x30 [117.004546] rest_init+0x104/0x200 [117.004548] start_kernel+0x93d/0xbd0 [117.004550] ? load_ucode_intel_bsp+0x2a/0x90 [117.004551] ? sme_unmap_bootdata+0x14/0x80 [117.004554] x86_64_start_reservations+0x18/0x30 [117.004555] x86_64_start_kernel+0xfd/0x150 [117.004556] ? soft_restart_cpu+0x14/0x14 [117.004558] common_startup_64+0x13e/0x141 [117.004560] </TASK> [117.004565] ------------[ cut here ]------------ [117.004692] WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1610 __timer_delete_sync+0x126/0x190 [117.004697] Modules linked in: vgem snd_hda_codec_intelhdmi snd_hda_codec_hdmi i915 prime_numbers ttm drm_buddy drm_display_helper cec rc_core i2c_algo_bit hid_sensor_custom hid_sensor_hub hid_generic intel_ishtp_hid hid intel_uncore_frequency intel_uncore_frequency_common x86_pkg_temp_thermal intel_powerclamp cmdlinepart ee1004 r8153_ecm spi_nor coretemp cdc_ether mei_pxp mei_hdcp usbnet mtd intel_rapl_msr wmi_bmof kvm_intel snd_hda_intel snd_intel_dspcfg processor_thermal_device_pci kvm snd_hda_codec processor_thermal_device irqbypass processor_thermal_wt_hint polyval_clmulni platform_temperature_control snd_hda_core ghash_clmulni_intel processor_thermal_rfim spi_pxa2xx_platform snd_hwdep aesni_intel processor_thermal_rapl dw_dmac snd_pcm dw_dmac_core intel_rapl_common r8152 rapl mii intel_cstate spi_pxa2xx_core i2c_i801 processor_thermal_wt_req snd_timer i2c_mux mei_me intel_ish_ipc processor_thermal_power_floor e1000e snd i2c_smbus spi_intel_pci processor_thermal_mbox mei soundcore intel_ishtp thunderbolt idma64 [117.004733] spi_intel int340x_thermal_zone igen6_edac binfmt_misc intel_skl_int3472_tps68470 intel_pmc_core tps68470_regulator video clk_tps68470 pmt_telemetry pmt_discovery nls_iso8859_1 pmt_class intel_pmc_ssram_telemetry intel_skl_int3472_discrete int3400_thermal intel_hid intel_skl_int3472_common acpi_thermal_rel intel_vsec wmi pinctrl_tigerlake acpi_tad sparse_keymap acpi_pad dm_multipath msr nvme_fabrics fuse efi_pstore nfnetlink autofs4 [117.004782] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G S U 6.17.0-rc7-CI_DRM_17270-g7644974e648c+ #1 PREEMPT(voluntary) [117.004787] Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER [117.004789] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR4 RVP, BIOS RPLPFWI1.R00.4035.A00.2301200723 01/20/2023 [117.004793] RIP: 0010:__timer_delete_sync+0x126/0x190 [117.004795] Code: 31 c0 45 31 c9 c3 cc cc cc cc 48 8b 75 d0 45 84 f6 74 63 49 c7 45 18 00 00 00 00 48 89 c7 e8 51 46 39 01 f3 90 e9 66 ff ff ff <0f> 0b e9 5f ff ff ff e8 ee e4 0c 00 49 8d 5d 28 45 31 c9 31 c9 4c [117.004801] RSP: 0018:ffffc90000003a40 EFLAGS: 00010046 [117.004804] RAX: ffffffff815093fb RBX: ffff888138f86aa8 RCX: 0000000000000000 [117.004807] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [117.004809] RBP: ffffc90000003a70 R08: 0000000000000000 R09: 0000000000000000 [117.004812] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff815093fb [117.004814] R13: ffff888138f86a80 R14: 0000000000000000 R15: 0000000000000000 [117.004817] FS: 0000000000000000(0000) GS:ffff88890b0f7000(0000) knlGS:0000000000000000 [117.004820] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [117.004823] CR2: 00005db8131eb7f0 CR3: 0000000003448000 CR4: 0000000000f52ef0 [117.004826] PKRU: 55555554 [117.004827] Call Trace: [117.004829] <IRQ> [117.004831] timer_delete_sync+0x10/0x20 [117.004833] vgem_fence_release+0x19/0x30 [vgem] [117.004836] dma_fence_release+0xc1/0x3b0 [117.004838] ? dma_fence_release+0xa1/0x3b0 [117.004841] dma_fence_chain_release+0xe7/0x130 [117.004844] dma_fence_release+0xc1/0x3b0 [117.004847] ? _raw_spin_unlock_irqrestore+0x27/0x80 [117.004850] dma_fence_chain_irq_work+0x59/0x80 [117.004853] irq_work_single+0x75/0xa0 [117.004857] irq_work_run_list+0x33/0x60 [117.004860] irq_work_run+0x18/0x40 [117.004863] __sysvec_irq_work+0x35/0x170 [117.004865] sysvec_irq_work+0x47/0xc0 [117.004868] asm_sysvec_irq_work+0x1b/0x20 [117.004871] RIP: 0010:_raw_spin_unlock_irqrestore+0x57/0x80 [117.004874] Code: 00 75 1c 65 ff 0d d9 34 68 01 74 20 5b 41 5c 5d 31 c0 31 d2 31 c9 31 f6 31 ff c3 cc cc cc cc e8 7f 9d d3 fe fb 0f 1f 44 00 00 <eb> d7 0f 1f 44 00 00 5b 41 5c 5d 31 c0 31 d2 31 c9 31 f6 31 ff c3 [117.004879] RSP: 0018:ffffc90000003cf0 EFLAGS: 00000246 [117.004882] RAX: 0000000000000000 RBX: ffff888155e94c40 RCX: 0000000000000000 [117.004884] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [117.004887] RBP: ffffc90000003d00 R08: 0000000000000000 R09: 0000000000000000 [117.004890] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000246 [117.004892] R13: 0000000000000001 R14: 0000000000000246 R15: ffff888155e94c80 [117.004897] dma_fence_signal+0x49/0xb0 [117.004899] ? __pfx_vgem_fence_timeout+0x10/0x10 [vgem] [117.004902] vgem_fence_timeout+0x12/0x20 [vgem] [117.004904] call_timer_fn+0xa1/0x2a0 [117.004908] ? __pfx_vgem_fence_timeout+0x10/0x10 [vgem] [117.004910] __run_timers+0x231/0x310 [117.004913] ? tmigr_handle_remote+0x2ac/0x560 [117.004917] timer_expire_remote+0x46/0x70 [117.004919] tmigr_handle_remote+0x433/0x560 [117.004923] ? __run_timers+0x239/0x310 [117.004925] ? run_timer_softirq+0x21/0xe0 [117.004928] ? lock_release+0xce/0x2a0 [117.004931] run_timer_softirq+0xcf/0xe0 [117.004933] handle_softirqs+0xd4/0x4d0 [117.004936] __irq_exit_rcu+0x13f/0x160 [117.004938] irq_exit_rcu+0xe/0x20 [117.004940] sysvec_apic_timer_interrupt+0xa0/0xc0 [117.004943] </IRQ> [117.004944] <TASK> [117.004946] asm_sysvec_apic_timer_interrupt+0x1b/0x20 [117.004949] RIP: 0010:cpuidle_enter_state+0x12b/0x8a0 [117.004953] Code: 48 0f a3 05 97 ce 0e 01 0f 82 2e 03 00 00 31 ff e8 8a 41 bd fe 80 7d d0 00 0f 85 11 03 00 00 e8 8b 06 d5 fe fb 0f 1f 44 00 00 <45> 85 f6 0f 88 67 02 00 00 4d 63 ee 49 83 fd 0a 0f 83 34 06 00 00 [117.004961] RSP: 0018:ffffffff83403d88 EFLAGS: 00000246 [117.004963] RAX: 0000000000000000 RBX: ffff88888f046440 RCX: 0000000000000000 [117.004966] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [117.004968] RBP: ffffffff83403dd8 R08: 0000000000000000 R09: 0000000000000000 [117.004971] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff837cbe80 [117.004974] R13: 0000000000000004 R14: 0000000000000004 R15: 0000001ad1df466b [117.004978] ? cpuidle_enter_state+0x125/0x8a0 [117.004981] ? sched_clock_noinstr+0x9/0x10 [117.004985] cpuidle_enter+0x2e/0x50 [117.004989] call_cpuidle+0x22/0x60 [117.004991] do_idle+0x1fd/0x260 [117.005001] cpu_startup_entry+0x29/0x30 [117.005004] rest_init+0x104/0x200 [117.005008] start_kernel+0x93d/0xbd0 [117.005011] ? load_ucode_intel_bsp+0x2a/0x90 [117.005014] ? sme_unmap_bootdata+0x14/0x80 [117.005017] x86_64_start_reservations+0x18/0x30 [117.005020] x86_64_start_kernel+0xfd/0x150 [117.005023] ? soft_restart_cpu+0x14/0x14 [117.005026] common_startup_64+0x13e/0x141 [117.005030] </TASK> [117.005032] irq event stamp: 2282669 [117.005034] hardirqs last enabled at (2282668): [<ffffffff8289db71>] _raw_spin_unlock_irqrestore+0x51/0x80 [117.005038] hardirqs last disabled at (2282669): [<ffffffff82882021>] sysvec_irq_work+0x11/0xc0 [117.005043] softirqs last enabled at (2254702): [<ffffffff8289fd00>] __do_softirq+0x10/0x18 [117.005047] softirqs last disabled at (2254725): [<ffffffff813d4ddf>] __irq_exit_rcu+0x13f/0x160 [117.005051] ---[ end trace 0000000000000000 ]---
Make the timer IRQ safe.
[1] https://patchwork.freedesktop.org/series/154987/#rev2
Fixes: 4077798484459 ("drm/vgem: Attach sw fences to exported vGEM dma-buf (ioctl)") Signed-off-by: Janusz Krzysztofik janusz.krzysztofik@linux.intel.com Reviewed-by: Christian König christian.koenig@amd.com Link: https://lore.kernel.org/r/20250926152628.2165080-2-janusz.krzysztofik@linux.... Signed-off-by: Maarten Lankhorst dev@lankhorst.se Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/vgem/vgem_fence.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vgem/vgem_fence.c b/drivers/gpu/drm/vgem/vgem_fence.c index e157541783959..d066345d5930b 100644 --- a/drivers/gpu/drm/vgem/vgem_fence.c +++ b/drivers/gpu/drm/vgem/vgem_fence.c @@ -94,7 +94,7 @@ static struct dma_fence *vgem_fence_create(struct vgem_file *vfile, dma_fence_init(&fence->base, &vgem_fence_ops, &fence->lock, dma_fence_context_alloc(1), 1);
- timer_setup(&fence->timer, vgem_fence_timeout, 0); + timer_setup(&fence->timer, vgem_fence_timeout, TIMER_IRQSAFE);
/* We force the fence to expire within 10s to prevent driver hangs */ mod_timer(&fence->timer, jiffies + VGEM_FENCE_TIMEOUT);